Thank you for reaching out helgaard81,
It sounds like you're trying to view the layout of the Nanjing International Airport, but the option isn't available. We can help.
First, let's follow these steps to Find nearby attractions, restaurants, and services in Maps on iPad and make sure we haven't missed anything:
Find your way around an airport or shopping mall
1. Do one of the following:
* Before you get there: Search for the airport or mall in Maps (tap Indoor Map if it appears in the search result). Or drag the map to show it, zoom in, then tap Look Inside.
* When you’re at the airport or mall: Open Maps, tap
, then tap Look Inside.
2. To find nearby services, tap a category (like Food, Restrooms, or Gates) on the place card, then scroll down to see all results. To get more information about a result, tap it.
3. To get a map of a different floor, tap the button showing the floor level (zoom in if the button doesn’t appear).

Note: Indoor maps are available for select airports and shopping malls. See the iOS and iPadOS Feature Availability website.
If you still don't see the option, you may want to scroll to the bottom of the Airport listing in Maps, and select "Report an Issue" to let Apple know.
Hope that helps.
Take care.